Utilization of null tones for urgent data transmission in Wi-Fi network

Embodiments described herein generally relate to wireless communication, and more specifically to utilization of null tones for urgent data transmission in a Wi-Fi network.

To increase overall throughput of Wi-Fi devices, transmit opportunity (TXOP) and frame aggregation was introduced in 802.11n and subsequent Wireless Local Area Network (WLAN) standards. The aggregation makes data payload of a Physical Protocol Data Unit (PPDU) much bigger and therefore occupies much longer transmission time.

Various aspects of the illustrative embodiments will be described using terms commonly employed by those skilled in the art to convey the substance of the disclosure to others skilled in the art. However, it will be apparent to those skilled in the art that many alternate embodiments may be practiced using portions of the described aspects. For purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to those skilled in the art that alternate embodiments may be practiced without the specific details. In other instances, well-known features may have been omitted or simplified in order to avoid obscuring the illustrative embodiments.

Further, various operations will be described as multiple discrete operations, in turn, in a manner that is most helpful in understanding the illustrative embodiments; however, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations need not be performed in the order of presentation.

is a network diagram of an example network environment in accordance with some example embodiments of the disclosure. As shown in, a wireless networkmay include one or more user devicesand one or more access points (APs), which may communicate in accordance with IEEE 802.11 communication standards. The user devicesmay be mobile devices that are non-stationary (e.g., not having fixed locations) or may be stationary devices.

In some embodiments, the user devicesand APsmay include one or more function modules similar to those in the functional diagram ofand/or the example machine/system of.

The one or more user devicesand/or APsmay be operable by one or more users. It should be noted that any addressable unit may be a station (STA). A STA may take on multiple distinct characteristics, each of which shape its function. For example, a single addressable unit might simultaneously be a portable STA, a quality-of-service (QoS) STA, a dependent STA, and a hidden STA. In addition, according to the IEEE 802.11 communication standards, a WLAN may include multiple basic service sets (BSSs). A network node in the BSS is a STA, and the STA includes access point-type stations (abbreviated as APs) and non-access point stations (abbreviated as non-AP STAs). Each BSS may include one AP and multiple non-AP STAs associated with the AP.

The one or more user devicesand/or APsmay operate as a personal basic service set (PBSS) control point/access point (PCP/AP). The user devices(e.g.,,, or) and/or APsmay include any suitable processor-driven device including, but not limited to, a mobile device or a non-mobile, e.g., a static device. For example, the user devicesand/or APsmay include, a user equipment (UE), a station (STA), an access point (AP), a software enabled AP (SoftAP), a personal computer (PC), a wearable wireless device (e.g., bracelet, watch, glasses, ring, etc.), a desktop computer, a mobile computer, a laptop computer, an Ultrabook™ computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a handheld device, an internet of things (IoT) device, a sensor device, a personal digital assistant (PDA) device, a handheld PDA device, an on-board device, an off-board device, a hybrid device (e.g., combining cellular phone functionalities with PDA device functionalities), a consumer device, a vehicular device, a non-vehicular device, a mobile or portable device, a non-mobile or non-portable device, a mobile phone, a cellular telephone, a personal communications service (PCS) device, a PDA device which incorporates a wireless communication device, a mobile or portable global positioning system (GPS) device, a digital video broadcasting (DVB) device, a relatively small computing device, a non-desktop computer, a “carry small live large” (CSLL) device, an ultra mobile device (UMD), an ultra mobile PC (UMPC), a mobile internet device (MID), an “origami” device or computing device, a device that supports dynamically composable computing (DCC), a context-aware device, a video device, an audio device, an AN device, a set-top-box (STB), a blu-ray disc (BD) player, a BD recorder, a digital video disc (DVD) player, a high definition (HD) DVD player, a DVD recorder, a HD DVD recorder, a personal video recorder (PVR), a broadcast HD receiver, a video source, an audio source, a video sink, an audio sink, a stereo tuner, a broadcast radio receiver, a flat panel display, a personal media player (PMP), a digital video camera (DVC), a digital audio player, a speaker, an audio receiver, an audio amplifier, a gaming device, a data source, a data sink, a digital still camera (DSC), a media player, a smartphone, a television, a music player, or the like. Other devices, including smart devices such as lamps, climate control, car components, household components, appliances, etc. may also be included in this list.

As used herein, the term “Internet of Things (IoT) device” is used to refer to any object (e.g., an appliance, a sensor, etc.) that has an addressable interface (e.g., an Internet protocol (IP) address, a Bluetooth identifier (ID), a near-field communication (NFC) ID, etc.) and can transmit information to one or more other devices over a wired or wireless connection. An IoT device may have a passive communication interface, such as a quick response (QR) code, a radio-frequency identification (RFID) tag, an NFC tag, or the like, or an active communication interface, such as a modem, a transceiver, a transmitter-receiver, or the like. An IoT device can have a particular set of attributes (e.g., a device state or status, such as whether the IoT device is on or off, open or closed, idle or active, available for task execution or busy, and so on, a cooling or heating function, an environmental monitoring or recording function, a light-emitting function, a sound-emitting function, etc.) that can be embedded in and/or controlled/monitored by a central processing unit (CPU), microprocessor, ASIC, or the like, and configured for connection to an IoT network such as a local ad-hoc network or the Internet. For example, IoT devices may include, but are not limited to, refrigerators, toasters, ovens, microwaves, freezers, dishwashers, dishes, hand tools, clothes washers, clothes dryers, furnaces, air conditioners, thermostats, televisions, light fixtures, vacuum cleaners, sprinklers, electricity meters, gas meters, etc., so long as the devices are equipped with an addressable communications interface for communicating with the IoT network. IoT devices may also include cell phones, desktop computers, laptop computers, tablet computers, personal digital assistants (PDAs), etc. Accordingly, the IoT network may be comprised of a combination of “legacy” Internet-accessible devices (e.g., laptop or desktop computers, cell phones, etc.) in addition to devices that do not typically have Internet-connectivity (e.g., dishwashers, etc.).

The user devicesand/or APsmay also include mesh stations in, for example, a mesh network, in accordance with one or more IEEE 802.11 standards and/or 3 GPP standards.

Any of the user devices(e.g., user devices,,) and APsmay be configured to communicate with each other via one or more communications networksand/orwirelessly or wired. The user devicesmay also communicate peer-to-peer or directly with each other with or without APs. Any of the communications networksand/ormay include, but not limited to, any one or a combination of different types of suitable communications networks such as, for example, broadcasting networks, cable networks, public networks (e.g., the Internet), private networks, wireless networks, cellular networks, or any other suitable private and/or public networks. Further, any of the communications networksand/ormay have any suitable communication range associated therewith and may include, for example, global networks (e.g., the Internet), metropolitan area networks (MANs), wide area networks (WANs), local area networks (LANs), or personal area networks (PANs). In addition, any of the communications networksand/ormay include any type of medium over which network traffic may be carried including, but not limited to, coaxial cable, twisted-pair wire, optical fiber, a hybrid fiber coaxial (HFC) medium, microwave terrestrial transceivers, radio frequency communication mediums, white space communication mediums, ultra-high frequency communication mediums, satellite communication mediums, or any combination thereof.

Any of the user devices(e.g., user devices,,) and APsmay include one or more communications antennas. The one or more communications antennas may be any suitable type of antennas corresponding to the communications protocols used by the user devices(e.g., user devices,and) and APs. Some non-limiting examples of suitable communications antennas include Wi-Fi antennas, Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards compatible antennas, directional antennas, non-directional antennas, dipole antennas, folded dipole antennas, patch antennas, multiple-input multiple-output (MIMO) antennas, omnidirectional antennas, quasi-omnidirectional antennas, or the like. The one or more communications antennas may be communicatively coupled to a radio component to transmit and/or receive signals, such as communications signals to and/or from the user devicesand/or APs.

Any of the user devices(e.g., user devices,,) and APsmay be configured to perform directional transmission and/or directional reception in conjunction with wirelessly communicating in a wireless network. Any of the user devices(e.g., user devices,,) and APsmay be configured to perform such directional transmission and/or reception using a set of multiple antenna arrays (e.g., DMG antenna arrays or the like). Each of the multiple antenna arrays may be used for transmission and/or reception in a particular respective direction or range of directions. Any of the user devices(e.g., user devices,,) and APsmay be configured to perform any given directional transmission towards one or more defined transmit sectors. Any of the user devices(e.g., user devices,,) and APsmay be configured to perform any given directional reception from one or more defined receive sectors.

MIMO beamforming in a wireless network may be accomplished using radio frequency (RF) beamforming and/or digital beamforming. In some embodiments, in performing a given MIMO transmission, the user devicesand/or APsmay be configured to use all or a subset of its one or more communications antennas to perform MIMO beamforming.

Any of the user devices(e.g., user devices,,) and APsmay include any suitable radio and/or transceiver for transmitting and/or receiving radio frequency (RF) signals in the bandwidth and/or channels corresponding to the communications protocols utilized by any of the user devicesand APsto communicate with each other. The radio components may include hardware and/or software to modulate and/or demodulate communications signals according to pre-established transmission protocols. The radio components may further have hardware and/or software instructions to communicate via one or more Wi-Fi and/or Wi-Fi direct protocols, as standardized by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. It should be understood that this list of communication channels in accordance with certain 802.11 standards is only a partial list and that other 802.11 standards may be used (e.g., Next Generation Wi-Fi, or other standards). In some embodiments, non-Wi-Fi protocols may be used for communications between devices, such as Bluetooth, dedicated short-range communication (DSRC), Ultra-High Frequency (UHF) (e.g. IEEE 802.11af, IEEE 802.22), white band frequency (e.g., white spaces), or other packetized radio communications. The radio component may include any known receiver and baseband suitable for communicating via the communications protocols. The radio component may further include a low noise amplifier (LNA), additional signal amplifiers, an analog-to-digital (A/D) converter, one or more buffers, and digital baseband.

To increase overall throughput of Wi-Fi devices, transmit opportunity (TXOP) and frame aggregation was introduced in 802.11n and subsequent Wireless Local Area Network (WLAN) standards. The aggregation makes data payload of a Physical Protocol Data Unit (PPDU) much bigger and therefore occupies much longer transmission time. Although frame aggregation helps to improve the overall throughput and reduce an average latency for a pair of STAs, it can result in a much higher worst-case latency for a third party STA waiting for the wireless medium to be idle due to a much longer airtime occupied by a long aggregated PPDU between the pair of STAs. Time-sensitive frames may experience a higher latency if the channel is occupied by a long PPDU transmission by other devices from the same BSS or overlapping BSS (OBSS).

In the disclosure, a mechanism for transmitting time sensitive traffic on top of the ongoing transmission will be described. According to embodiments of the disclosure, it is proposed to utilize null tones allocated in the PPDU for transmission of time sensitive traffic.

At present, the IEEE has published tone plans (subcarrier allocation patterns) for the 802.11ax system, which supports OFDMA transmission, and the tone plans with respective bandwidths of 80 MHz, 160 MHz and 320 MHz are shown into. The tone plans specify the locations of frequency resource units (RUs) including guard subcarriers (edge tones), data subcarriers (data tones), null subcarriers (null tones) and Direct Current (DC) subcarriers (DC tones). As shown in the figures, 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs and 996-tone RUs can be allocated using OFDMA transmission.

As shown into, the tone plans specify DC tones and different null tones for the PPDUs of different bandwidths. These null tones or DC tones do not have energy populated for different reasons. For instance, DC tones do not have energy populated because they are adjacent to DC. Other null tones far from the DC tones are simply set because of tone plan design. These tones are mostly wasted in the current Extremely High Throughput (EHT) PPDU transmission. However, these null tones or DC tones can be harvested and used for low rate transmission of urgent data. An example of the urgent data is time sensitive control information.

According to embodiments of the disclosure, when there is urgent data in a Wi-Fi network to be transmitted, a PPDU carrying the urgent data may be generated for transmission to a receiver of the PPDU, and the urgent data may be carried over one or more null tones in the PPDU. The one or more null tones may be determined based on a bandwidth of the PPDU and a transmission mode of the PPDU. The bandwidth of the PPDU and the transmission mode of the PPDU may be indicated by a universal signaling field (U-SIG) in a preamble of the PPDU, such that the receiver will know which tones may carry the urgent data in downlink or uplink transmission by performing preamble detection.

With reference to, for the PPDU of 80 MHz, when the transmission mode of the PPDU is Orthogonal Frequency-Division Multiple Access (OFDMA) transmission, there are 23 DC tones in total but 5 DC tones are required as DC nulls, and thus 18 DC tones can be utilized for transmission of urgent data. In addition, there are 5 null tones (between two 242-tone RUs) in a lower bandwidth of 40 MHz and 5 null tones (also between two 242-tone RUs) in an upper bandwidth of 40 MHz respectively, which makes another 10 null tones in total to be utilized for transmission of urgent data. Therefore, for the PPDU of 80 MHz with OFDMA transmission, 28 null tones in total can be utilized for transmission of urgent data. For the PPDU of 80 MHz with non-OFDMA transmission, there is no null tone that can be used.

With reference to, for the PPDU of 160 MHz, when the transmission mode of the PPDU is OFDMA transmission, there are also 18 DC tones that can be utilized for transmission of urgent data. In addition, there are 33 null tones (including 23 null tones between two 484-tone RUs and a pair of 5 null tones between two 242-tone RUs) in a lower bandwidth of 80 MHz and 33 null tones (including 23 null tones between two 484-tone RUs and a pair of 5 null tones between two 242-tone RUs) in an upper bandwidth of 80 MHz respectively, which makes another 66 null tones in total to be utilized for transmission of urgent data. Therefore, for the PPDU of 160 MHz with OFDMA transmission, 84 null tones in total can be utilized for transmission of urgent data. For the PPDU of 160 MHz with non-OFDMA transmission, there are 18 DC tones, 5 null tones in the lower bandwidth of 80 MHz and 5 null tones in the upper bandwidth of 80 MHz that can be used, and thus 28 null tones in total can be utilized for transmission of urgent data.

With reference to, for the PPDU of 320 MHz, when the transmission mode of the PPDU is OFDMA transmission, there are also 18 DC tones that can be utilized for transmission of urgent data. In addition, there are 89 null tones (including 23 null tones between two 996-tone RUs, a pair of 23 null tones between two 484-tone RUs, and 4×5 null tones between two 242-tone RUs) in a lower bandwidth of 160 MHz and 89 null tones (including 23 null tones between two 996-tone RUs, a pair of 23 null tones between two 484-tone RUs, and 4×5 null tones between two 242-tone RUs) in an upper bandwidth of 160 MHz respectively, which makes another 178 null tones in total to be utilized for transmission of urgent data. Therefore, for the PPDU of 160 MHz with OFDMA transmission, 196 null tones in total can be utilized for transmission of urgent data. For the PPDU of 320 MHz with non-OFDMA transmission, there are 18 DC tones, 33 null tones in the lower bandwidth of 160 MHz and 33 null tones in the upper bandwidth of 160 MHz that can be used, and thus 84 null tones in total can be utilized for transmission of urgent data.

It is noted that for sake of clarity, the tone plans shown inandare simplified tone plans only illustrating the null tones to be utilized for urgent transmission.

According to the illustration into, in some embodiments of the disclosure, when the bandwidth of the PPDU is 80 MHz and the transmission mode of the PPDU is OFDMA transmission, the one or more null tones for transmitting the urgent data may be selected from a pre-specified null tone set including 18 DC tones, 5 null tones in a lower bandwidth of 40 MHz and 5 null tones in an upper bandwidth of 40 MHz in the PPDU; when the bandwidth of the PPDU is 160 MHz and the transmission mode of the PPDU is OFDMA transmission, the one or more null tones for transmitting the urgent data may be selected from a pre-specified null tone set including 18 DC tones, 33 null tones in a lower bandwidth of 80 MHz and 33 null tones in an upper bandwidth of 80 MHz in the PPDU; when the bandwidth of the PPDU is 160 MHz and the transmission mode of the PPDU is non-OFDMA transmission, the one or more null tones for transmitting the urgent data may be selected from a pre-specified null tone set comprising 18 DC tones, 5 null tones in a lower bandwidth of 80 MHz and 5 null tones in an upper bandwidth of 80 MHz in the PPDU; when the bandwidth of the PPDU is 320 MHz and the transmission mode of the PPDU is OFDMA transmission, the one or more null tones for transmitting the urgent data may be selected from a pre-specified null tone set comprising 18 DC tones, 89 null tones in a lower bandwidth of 160 MHz and 89 null tones in an upper bandwidth of 160 MHz in the PPDU; when the bandwidth of the PPDU is 320 MHz and the transmission mode of the PPDU is non-OFDMA transmission, the one or more null tones for transmitting the urgent data may be selected from a pre-specified null tone set comprising 18 DC tones, 33 null tones in a lower bandwidth of 160 MHz and 33 null tones in an upper bandwidth of 160 MHz in the PPDU.

According to embodiments of the disclosure, by use of the null tones for urgent transmission, the PPDU may include a preamble, the urgent data carried over the one or more null tones, and regular data carried over RUs in the PPDU.shows an example PPDU carrying urgent data over null tones according to some embodiments of the present disclosure. As shown in, the preamble may include information for the receiver to estimate a channel on the one or more null tones for transmitting the urgent data, and a waveform of the urgent data may be orthogonal in a frequency domain to a waveform of the regular data.

Below some example use cases will be provided to describe further details about utilizing the null tones for transmission of urgent data.

In an example use case, an AP or a non-AP STA may have already obtained the TxOP and have unscheduled urgent low rate traffic to be transmitted while transmitting regular data. In this case, the AP or non-AP STA can send the urgent low rate traffic on the null tones together with the regular data as shown in. The waveform of the urgent low rate traffic may be orthogonal in the frequency domain to the waveform of the regular data. The urgent low rate traffic can be transmitted with a normal OFDMA data format and carried over the null tones. On the other hand, a receiver of the urgent low rate traffic may need to receive the preamble in the PPDU and estimate the channel on the null tones carrying the urgent low rate traffic by performing preamble detection. The receiver may also need to keep the phase tracking till the end of the PPDU in case urgent traffic shows up in any symbol of the PPDU.

In another example use case, an AP may have already obtained the TxOP and triggered multiple non-AP STAs to transmit uplink data using a UL-MU-OFDMA format. During the uplink OFDMA data transmission, if a non-AP STA has unscheduled urgent low rate traffic to be transmitted, the non-AP STA can synchronize with the AP based on a trigger frame from the AP and send the urgent low rate traffic on the null tones together with the regular data as shown in. The AP may be in a same BSS or an overlapping BSS with the non-AP STA. The waveform of the urgent low rate traffic may be orthogonal in the frequency domain to the waveform of regular data. The urgent low rate traffic can be transmitted with a normal OFDMA data format and carried over the null tones. On the other hand, the AP may need to estimate the channel on the null tones carrying the urgent low rate traffic by performing preamble detection. Therefore, when the non-AP STA sends the urgent low rate traffic, it may need to indicate the start of the urgent low rate traffic following a LTF in the preamble of the PPDU. As a result, the AP can do channel estimation and decode the urgent low rate traffic.

In a further example use case, the AP and the non-STA AP may be in a managed synchronized network, such as a wireless time sensitive network, where all the wireless devices in the network are time and frequency synchronized to a central controller. If the AP or the non-AP STA is in the managed synchronized network and uses a fixed channel bandwidth of 80 MHz, 160 MHz or 320 MHz for data transmission, all the devices within the network may be aware of a common null tone set for urgent transmission and the AP or the non-AP STA can send unscheduled urgent low rate traffic on one or more null tones selected from the common null tone set. If the AP or the non-AP STA uses a dynamic channel bandwidth for data transmission and the devices are aware of the transmission bandwidth of the on-going data transmission upon the preamble detection, the AP or the non-AP STA can also send unscheduled urgent low data traffic on the null tones of the current busy channel.

As described above, it is proposed to utilize null tones in the PPDU for urgent data transmission in Wi-Fi networks in the disclosure.is a flowchart illustrating example operations for utilization of null tones for urgent data transmission in a Wi-Fi network according to some embodiments of the present disclosure. The operations may include operationsto.

At operation, an apparatus having urgent data to transmit may generate a PPDU carrying the urgent data over one or more null tones in the PPDU.

According to embodiments of the disclosure, the one or more null tones may be determined based on a bandwidth of the PPDU and a transmission mode of the PPDU. The bandwidth of the PPDU and the transmission mode of the PPDU may be indicated by a universal signaling field (U-SIG) in a preamble of the PPDU.

In some embodiments, when the bandwidth of the PPDU is 80 MHz and the transmission mode is OFDMA transmission, the one or more null tones may be selected from a pre-specified null tone set comprising 18 DC tones, 5 null tones in a lower bandwidth of 40 MHz and 5 null tones in an upper bandwidth of 40 MHz in the PPDU.

In some embodiments, when the bandwidth of the PPDU is 160 MHz and the transmission mode is OFDMA transmission, the one or more null tones may be selected from a pre-specified null tone set comprising 18 DC tones, 33 null tones in a lower bandwidth of 80 MHz and 33 null tones in an upper bandwidth of 80 MHz in the PPDU.

In some embodiments, when the bandwidth of the PPDU is 160 MHz and the transmission mode is non-OFDMA transmission, the one or more null tones may be selected from a pre-specified null tone set comprising 18 DC tones, 5 null tones in a lower bandwidth of 80 MHz and 5 null tones in an upper bandwidth of 80 MHz in the PPDU.

In some embodiments, when the bandwidth of the PPDU is 320 MHz and the transmission mode is OFDMA transmission, the one or more null tones may be selected from a pre-specified null tone set comprising 18 DC tones, 89 null tones in a lower bandwidth of 160 MHz and 89 null tones in an upper bandwidth of 160 MHz in the PPDU.

In some embodiments, when the bandwidth of the PPDU is 320 MHz and the transmission mode is non-OFDMA transmission, the one or more null tones are selected from a pre-specified null tone set comprising 18 DC tones, 33 null tones in a lower bandwidth of 160 MHz and 33 null tones in an upper bandwidth of 160 MHz in the PPDU.

At operation, the apparatus may transmit the PPDU to a receiver of the PPDU.

According to embodiments of the disclosure, the PPDU may include a preamble, the urgent data carried over the one or more null tones, and regular data carried over RUs in the PPDU. The preamble may include information for the receiver to estimate a channel on the one or more null tones, and a waveform of the urgent data may be orthogonal in a frequency domain to a waveform of the regular data.

In some embodiments, the apparatus may be applied in an AP or a non-AP STA having already obtained a TxOP.

In some embodiments, the apparatus may be applied in a non-AP STA triggered to transmit data by an AP having already obtained a TxOP. The apparatus may be further configured to synchronize the non-AP STA with the AP based on a trigger frame from the AP. The AP may be in a same BSS or an overlapping BSS with the non-AP STA.

In some embodiments, the apparatus may be applied in an AP or a non-AP STA in a managed synchronized network where all wireless devices are time and frequency synchronized to a central controller. When the AP or the non-AP STA uses a fixed channel bandwidth for data transmission, the one or more null tones may be selected from a common null tone set pre-specified for all the wireless devices in the managed synchronized network.

shows a functional diagram of an exemplary communication station, in accordance with one or more example embodiments of the disclosure. In one embodiment,illustrates a functional block diagram of a communication station that may be suitable for use as the AP() or the user device() in accordance with some embodiments. The communication stationmay also be suitable for use as a handheld device, a mobile device, a cellular telephone, a smartphone, a tablet, a netbook, a wireless terminal, a laptop computer, a wearable computer device, a femtocell, a high data rate (HDR) subscriber station, an access point, an access terminal, or other personal communication system (PCS) device.

The communication stationmay include communications circuitryand a transceiverfor transmitting and receiving signals to and from other communication stations using one or more antennas. The communications circuitrymay include circuitry that can operate the physical layer (PHY) communications and/or medium access control (MAC) communications for controlling access to the wireless medium, and/or any other communications layers for transmitting and receiving signals. The communication stationmay also include processing circuitryand memoryarranged to perform the operations described herein. In some embodiments, the communications circuitryand the processing circuitrymay be configured to perform operations detailed in the above figures, diagrams, and flows.

In accordance with some embodiments, the communications circuitrymay be arranged to contend for a wireless medium and configure frames or packets for communicating over the wireless medium. The communications circuitrymay be arranged to transmit and receive signals. The communications circuitrymay also include circuitry for modulation/demodulation, upconversion/downconversion, filtering, amplification, etc. In some embodiments, the processing circuitryof the communication stationmay include one or more processors. In other embodiments, two or more antennasmay be coupled to the communications circuitryarranged for transmitting and receiving signals. The memorymay store information for configuring the processing circuitryto perform operations for configuring and transmitting message frames and performing the various operations described herein. The memorymay include any type of memory, including non-transitory memory, for storing information in a form readable by a machine (e.g., a computer). For example, the memorymay include a computer-readable storage device, read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices and other storage devices and media.

In some embodiments, the communication stationmay be part of a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), a wearable computer device, or another device that may receive and/or transmit information wirelessly.

In some embodiments, the communication stationmay include one or more antennas. The antennasmay include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas, or other types of antennas suitable for transmission of RF signals. In some embodiments, instead of two or more antennas, a single antenna with multiple apertures may be used. In these embodiments, each aperture may be considered a separate antenna. In some multiple-input multiple-output (MIMO) embodiments, the antennas may be effectively separated for spatial diversity and the different channel characteristics that may result between each of the antennas and the antennas of a transmitting station.

In some embodiments, the communication stationmay include one or more of a keyboard, a display, a non-volatile memory port, multiple antennas, a graphics processor, an application processor, speakers, and other mobile device elements. The display may be a liquid crystal display (LCD) screen including a touch screen.

Although the communication stationis illustrated as having several separate functional elements, two or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may include one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements of the communication stationmay refer to one or more processes operating on one or more processing elements.